Folding plunger assembly for blanking system

Abstract

A plunger assembly is provided for gripping blanking material or blanking scrap during a blanking operation. The plunger assembly includes a base member; a pivoting gripper or plunger member, and a pair of connecting legs connecting the pivoting gripper member to the base member. The assembly is adapted to pivot with respect to at least one of the base member and the pivoting gripper member through a predetermined pivot angle range for changing a distance between the base member and the pivoting gripper member. By pivoting, a folding and unfolding of the plunger assembly can be effected during a blanking operation.

What is claimed is:  
     
       1. A plunger assembly for gripping blanking material during a blanking operation, said plunger assembly comprising: 
       a base member;  
       a pivoting gripper member;  
       a biasing device; and  
       at least one pair of connecting legs, said at least one pair of connecting legs including a gripper leg and a base leg pivotally connected to one another, said gripper leg also being pivotably connected to said pivoting gripper member, said base leg also being pivotably connected to said base member, and said pivoting gripper member being pivotable with respect to said gripper leg through a predetermined pivot angle range, said gripped leg and said base leg being pivotable with respect to one another for changing a distance between the pivoting gripper member and the base member, thereby selectively effecting a folding and unfolding of the plunger assembly during a blanking operation, wherein the biasing device biases the pivoting gripper member away from the base member.  
     
     
       2. The plunger assembly according to  claim 1 , wherein said at least one pair of connecting legs comprises two pairs of connecting legs that are mirror images of each other. 
     
     
       3. The plunger assembly according to  claim 1 , wherein the biasing device is disposed for biasing the base leg away from the gripper leg and into an unfolded position. 
     
     
       4. The plunger assembly according to  claim 1 , wherein the biasing device comprises a torsion spring. 
     
     
       5. The plunger assembly according to  claim 2 , further comprising a biasing device for each pair of connecting legs, each biasing device comprising a torsion spring disposed at a pivot joint between the base leg and gripper leg of each pair of connecting legs. 
     
     
       6. The plunger assembly according to  claim 1 , wherein the biasing device comprises a torsion spring having a first spring arm that bears against the base leg, and a second spring arm that bears against the gripper leg. 
     
     
       7. The plunger assembly according to  claim 6 , further including a pivot pin that passes through the base leg, the gripper leg, and the torsion spring, said base leg and said gripper leg pivoting with respect to one another on said pivot pin. 
     
     
       8. The plunger assembly according to  claim 2 , wherein the pivoting gripper member includes a downwardly projecting flange thereon, and the gripper leg of each pair of connecting legs is pivotally connected to the projecting flange. 
     
     
       9. The plunger assembly according to  claim 2 , wherein the gripper leg of each pair of connecting legs includes a trough, and the respective base leg of each pair of connecting legs is received in said trough in a fully folded state of the plunger assembly. 
     
     
       10. The plunger assembly according to  claim 2 , wherein the gripper leg of each pair of connecting legs includes: 
       a slot at a first end thereof, and  
       the pivoting gripper member includes a downwardly projecting flange and wherein a respective gripper leg is pivotally connected to the flange such that the flange is received within said slot of said respective gripper leg.  
     
     
       11. The plunger assembly according to  claim 2 , wherein: 
       the base leg of each pair of connecting legs includes a slot at an end thereof; and  
       the base member includes a first projecting flange and a second projecting flange, wherein the base legs of the two pairs of connecting legs are respectively pivotally connected to the first projecting flange and the second projecting flange such that the first projecting flange and the second projecting flange are respectfully received within the corresponding slots of the base legs.  
     
     
       12. The plunger assembly according to  claim 2 , wherein pivot pins are provided at connections between the pivoting gripper member and the gripper legs, between the gripper legs and the respective base legs, and between the base legs and the base member. 
     
     
       13. The plunger assembly according to  claim 1 , wherein the at least one pair of connecting legs is configured for effecting a folding of the plunger assembly such that, in a fully folded state of the plunger assembly, the base member, the base leg, the gripper leg, and the pivoting gripper member are substantially parallel to one another. 
     
     
       14. A kit including components for forming at least one plunger assembly for gripping blanking material during a blanking operation, said kit comprising at least one base member; a pivoting gripper member adapted to be connected to the base member; at least one pair of pivotable connecting legs adapted to connect the base member to the pivoting gripper member, said pair of connecting legs adapted to pivot with respect to at least one of the base member and the pivoting gripper member in an assembled state of the plunger assembly through a predetermined pivot angle for changing a distance between the base member and the pivoting gripper member; and a biasing device to bias the pivotable connecting legs into a position that maximizes the distance between the base member and the pivoting gripper member. 
     
     
       15. The kit of  claim 14 , further comprising components for forming at least one folding presser assembly for supporting blanking scrap during a blanking operation, said components for forming the at least one presser assembly comprising: 
       a support rail;  
       a presser rail connected to the support rail; and  
       a connecting rail connecting the presser rail to the support rail and being adapted to pivot with respect to at least one of the support rail and the presser rail through a predetermined pivot angle range for changing the distance between the support rail and the presser rail thereby selectively effecting a folding and unfolding of the presser assembly during the blanking operation.  
     
     
       16. A system for gripping a blanking sheet, said system including at least one folding presser assembly and at least one plunger assembly, 
       said folding presser assembly comprising: a support rail, a presser rail connected to the support rail; and a connecting rail connecting the presser rail to the support rail and being adapted to pivot with respect to at least one of the support rail and the presser rail through a predetermined pivot angle range for changing the distance between the support rail and the presser rail thereby selectively effecting a folding and unfolding of the presser assembly during the blanking operation, and  
       said plunger assembly comprising: a base member; a pivoting gripper member; and at least one pair of connecting legs connecting the base member to the pivoting gripper member, said pair of connecting legs including a gripper leg and a base leg pivotally connected to one another, said gripper leg also being pivotally connected to the pivoting gripper member so as to be pivotable through a predetermined pivot angle range and said base leg being pivotally connected to the base member so as to be pivotable through a predetermined pivot angle range for changing a distance between the pivoting gripper member and the base member to thereby selectively effect a folding and unfolding of the plunger assembly during a blanking operation.  
     
     
       17. The system of  claim 16 , further comprising a blanking press platen, and wherein said presser assembly and said plunger assembly are attached to the blanking press platen.